Apparatus and method for an asphalt mix temperature control system

ABSTRACT

A control system for controlling the temperature of the asphalt mix comprising a recycled asphalt pavement source that is adapted to provide an amount of recycled asphalt pavement, a recycled asphalt pavement sensor that is adapted to determine an amount of RAP moisture contained in the amount of recycled asphalt pavement, a liquid asphalt cement source that is adapted to provide an amount of liquid asphalt cement, a liquid asphalt cement meter that is adapted to determine the amount of liquid asphalt cement provided by the liquid asphalt cement source, a burner assembly having a variable firing rate, a dryer, and a controller that is adapted to communicate with the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, and the burner assembly. The controller automatically controls the variable firing rate of the burner assembly.

CROSS-REFERENCES TO RELATED APPLICATIONS/PATENTS

This application relates back to and claims the benefit of priority from U.S. Provisional Application for Patent Ser. No. 61/959,111 entitled “Feed Forward Burner Control” and filed on Aug. 15, 2013.

FIELD OF THE INVENTION

The present invention relates generally to control systems for controlling the temperature of an asphalt mix, and particularly to automated control systems for controlling the temperature of an asphalt mix by controlling the firing rate of a burner assembly.

BACKGROUND AND DESCRIPTION OF THE PRIOR ART

It is known to use control systems for controlling the temperature of an asphalt mix. Conventional control systems used to control the temperature of an asphalt mix, however, suffer from one or more disadvantages. For example, conventional control systems for controlling the temperature of an asphalt mix are not substantially completely automated. More particularly, conventional control systems for controlling the temperature of an asphalt mix do not collect data relating to operating conditions from multiple sources in an asphalt plant substantially continuously and substantially in real time. Further, conventional control systems for controlling the temperature of an asphalt mix do not analyze operating conditions data from multiple sources in an asphalt plant and calculate an optimal firing rate for a burner assembly based upon the operating conditions data substantially continuously and substantially in real time. Still further, conventional control systems for controlling the temperature of an asphalt mix do not control the firing rate of a burner assembly substantially continuously and substantially in real time. As a result, conventional control systems for controlling the temperature of an asphalt mix do not include a burner assembly that fires at an optimal firing rate substantially continuously. Consequently, conventional control systems for controlling the temperature of an asphalt mix produce an asphalt mix that is either over-heated or under-heated. Further, conventional control systems for controlling the temperature of an asphalt mix do not maximize burner assembly and material efficiency or minimize costly fuel consumption. Still further, conventional control systems for controlling the temperature of an asphalt mix require excessive human labor for monitoring and adjustments.

It would be desirable, therefore, if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would be substantially completely automated. It would also be desirable if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would collect data relating to operating conditions from multiple sources in an asphalt plant substantially continuously and substantially in real time. It would be further desirable if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would analyze operating conditions data from multiple sources in an asphalt plant and calculate an optimal firing rate for a burner assembly based upon the operating conditions data substantially continuously and substantially in real time. It would be still further desirable if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would control the firing rate of a burner assembly substantially continuously and substantially in real time.

In addition, it would be desirable if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would include a burner assembly that fires at an optimal firing rate substantially continuously. Further, it would be desirable if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would produce an asphalt mix that is neither over-heated nor under-heated. Still further, it would also be desirable if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would maximize burner assembly and material efficiency and minimize costly fuel consumption. It would also be desirable if an apparatus and method for a control system for controlling the temperature of an asphalt mix could be provided that would minimize or eliminate human labor for monitoring and adjustments.

Advantages of the Preferred Embodiments of the Invention

Accordingly, it is an advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that is substantially completely automated. It is also an advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that collects data relating to operating conditions from multiple sources in an asphalt plant substantially continuously and substantially in real time. It is another advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that analyzes operating conditions data from multiple sources in an asphalt plant and calculates an optimal firing rate for a burner assembly based upon the operating conditions data substantially continuously and substantially in real time. It is a further advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that controls the firing rate of a burner assembly substantially continuously and substantially in real time. It is a still further advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that includes a burner assembly that fires at an optimal firing rate substantially continuously.

In addition, it is an advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that produces an asphalt mix that is neither over-heated nor under-heated. It is still another advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that maximizes burner assembly and material efficiency and minimizes costly fuel consumption. It is yet another advantage of the preferred embodiments of the invention claimed herein to provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that minimizes or eliminates human labor for monitoring and adjustments.

Additional advantages of the preferred embodiments of the invention will become apparent from an examination of the drawings and the ensuing description.

SUMMARY OF THE INVENTION

The apparatus of the invention comprises a control system for controlling the temperature of the asphalt mix. The preferred control system comprises a recycled asphalt pavement source that is adapted to provide an amount of recycled asphalt pavement to the asphalt mix, a recycled asphalt pavement sensor that is adapted to determine an amount of RAP moisture contained in the amount of recycled asphalt pavement, a liquid asphalt cement source that is adapted to provide an amount of liquid asphalt cement to the asphalt mix, and a liquid asphalt cement meter that is adapted to determine the amount of liquid asphalt cement provided by the liquid asphalt cement source to the asphalt mix. The preferred control system also comprises a burner assembly having a variable firing rate, a dryer that disposed adjacent the burner assembly, and a controller that is adapted to communicate with the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, and the burner assembly. In the preferred embodiments of the control system, the controller automatically controls the variable firing rate of the burner assembly.

The method of the invention comprises a method for controlling the temperature of an asphalt mix. The preferred method comprises providing a control system for controlling the temperature of the asphalt mix. The preferred control system comprises a recycled asphalt pavement source that is adapted to provide an amount of recycled asphalt pavement to the asphalt mix, a recycled asphalt pavement sensor that is adapted to determine an amount of RAP moisture contained in the amount of recycled asphalt pavement, a liquid asphalt cement source that is adapted to provide an amount of liquid asphalt cement to the asphalt mix, and a liquid asphalt cement meter that is adapted to determine the amount of liquid asphalt cement provided by the liquid asphalt cement source to the asphalt mix. The preferred control system also comprises a burner assembly having a variable firing rate, a dryer that disposed adjacent the burner assembly, and a controller that is adapted to communicate with the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, and the burner assembly. In the preferred embodiments of the control system, the controller automatically controls the variable firing rate of the burner assembly. The preferred method also comprises automatically controlling the variable firing rate of the burner assembly.

BRIEF DESCRIPTION OF THE DRAWINGS

The presently preferred embodiments of the invention are illustrated in the accompanying drawing, in which like reference numerals represent like parts throughout, and in which:

FIG. 1 is a top view of an exemplary asphalt plant including the preferred embodiment of the control system for controlling the temperature of an asphalt mix in accordance with the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS OF THE INVENTION

Referring now to the drawing, the preferred embodiment of the control system for controlling the temperature of an asphalt mix in accordance with the present invention is illustrated by FIG. 1. As shown in FIG. 1, the preferred control system for controlling the temperature of an asphalt mix is adapted to collect and analyze data relating to operating conditions from multiple sources in an asphalt plant substantially continuously and substantially in real time. More particularly, the preferred control system for controlling the temperature of an asphalt mix is adapted to collect and analyze the following data: (i) virgin aggregate mass flow rate; (ii) virgin aggregate moisture content; (iii) recycled asphalt pavement (RAP) mass flow rate; (iv) RAP moisture content; (v) recycled asphalt shingles (RAS) mass flow rate; (vi) RAS moisture content; (vii) liquid asphalt cement mass flow rate; (viii) liquid asphalt cement temperature (optional); (ix) injected water mass flow rate (for making warm asphalt mix); (x) injected water temperature; (xi) exhaust gas temperature (at the baghouse inlet); (xii) baghouse humidity (optional); and (xiii) final asphalt mix temperature. Based on the foregoing data, the preferred control system for controlling the temperature of an asphalt mix calculates an optimal firing rate for a burner assembly and automatically controls the firing rate of the burner assembly substantially continuously and substantially in real time. In short, the preferred control system automatically, substantially continuously, and substantially in real time determines the heat demand required by the incoming components of an asphalt mix before the components are introduced into a dryer and exposed to a burner assembly.

Referring now to FIG. 1, a top view of an exemplary asphalt plant including the preferred embodiment of the control system for controlling the temperature of an asphalt mix in accordance with the present invention is illustrated. As shown in FIG. 1, the preferred control system is designated generally by reference numeral 10. Preferred control system 10 comprises a recycled asphalt pavement source which is adapted to provide an amount of recycled asphalt pavement to the asphalt mix. The preferred asphalt source comprises a container such as coarse RAP bin 22 and fines RAP bin 24 which are adapted to receive, hold, and discharge an amount of recycled asphalt pavement. Preferably, the amount of recycled asphalt pavement is conveyed from the recycled asphalt pavement source by conveyor belt assembly 26 or any other suitable device, mechanism, assembly, or combination thereof adapted to convey an amount of recycled asphalt pavement. Preferred conveyor belt assembly 26 also comprises belt scale 28 which is adapted to weigh the amount of recycled asphalt pavement on the conveyor belt assembly. It is contemplated within the scope of the invention, however, that the recycled asphalt pavement source may determine the amount of recycled asphalt pavement provided to the asphalt mix by any suitable means such as weight, volume, and the like. Preferred control system 10 also comprises RAP screens 30 which are adapted to screen the amount of recycled asphalt pavement before it is mixed with the other components of the asphalt mix. While FIG. 1 illustrates the preferred configuration and arrangement of the recycled asphalt pavement source, it is contemplated within the scope of the invention that the recycled asphalt pavement source may be of any suitable configuration and arrangement.

Still referring to FIG. 1, preferred control system 10 also comprises recycled asphalt pavement moisture sensor 40 which is adapted to determine an amount of RAP moisture contained in the amount of recycled asphalt pavement. Preferred recycled asphalt pavement moisture sensor 40 may be any suitable type of sensor adapted to determine the amount of RAP moisture contained in the amount of recycled asphalt pavement such as an infrared sensor, a microwave sensor, a radioactive material based sensor, and the like. While FIG. 1 illustrates the preferred configuration and arrangement of the recycled asphalt pavement sensor, it is contemplated within the scope of the invention that the recycled asphalt pavement sensor may be of any suitable configuration and arrangement. It is also contemplated within the scope of the invention that more than one recycled asphalt pavement sensor may be provided.

Still referring to FIG. 1, preferred control system 10 further comprises liquid asphalt cement source 50 which is adapted to provide an amount of liquid asphalt cement to the asphalt mix. Preferred liquid asphalt cement source 50 comprises a container such as liquid asphalt cement tanks 52, 54, 56, and 58. Preferred liquid asphalt cement tanks 52, 54, 56, and 58 are adapted to receive, hold, and discharge an amount of liquid asphalt cement. Preferably, the amount of liquid asphalt cement is conveyed from preferred liquid asphalt cement tanks 52, 54, 56, and 58 via a conduit, pipe, tube, or any other suitable device, mechanism, assembly, or combination thereof adapted to convey an amount of liquid asphalt cement. Preferred liquid asphalt cement source 50 also comprises a means for conveying the amount of liquid asphalt cement from the preferred liquid asphalt cement tanks 52, 54, 56, and 58 such as pump 59. Preferred pump 59 is adapted to vary the flow rate of liquid asphalt cement from the container to the asphalt mix. It is contemplated within the scope of the invention, however, that any suitable device, mechanism, assembly, or combination thereof may be used to convey the amount of liquid asphalt cement from the container. While FIG. 1 illustrates the preferred configuration and arrangement of the liquid asphalt cement source, it is contemplated within the scope of the invention that the liquid asphalt cement source may be of any suitable configuration and arrangement.

Still referring to FIG. 1, preferred control system 10 still further comprises liquid asphalt cement meter 60 which is adapted to determine the amount of liquid asphalt cement provided by liquid asphalt cement source 50 to the asphalt mix. Preferred liquid asphalt cement meter 60 is adapted to determine the mass flow rate of the amount of liquid asphalt cement provided by the liquid asphalt cement source 50. It is contemplated within the scope of the invention, however, that the liquid asphalt cement meter may determine the amount of liquid asphalt cement provided by the liquid asphalt cement source by any suitable means such as weight, volume, and the like. It is also contemplated within the scope of the invention that more than one liquid asphalt cement meter may be provided. It is further contemplated within the scope of the invention that the liquid asphalt cement meter may be adapted to determine the temperature of the amount of liquid asphalt cement provided by the liquid asphalt cement source to the asphalt mix or that the temperature of the amount of liquid asphalt cement may be determined by any suitable device, mechanism, assembly, or combination thereof.

Still referring to FIG. 1, preferred control system 10 also includes aggregate material source 70 which is adapted to provide an amount of aggregate material to the asphalt mix. Preferred aggregate material source 70 comprises a container such as cold feed bins 72. Preferred cold feed bins 72 are adapted to receive, hold, and discharge an amount of aggregate material. Preferably, the amount of aggregate material is conveyed from aggregate material source 70 by aggregate material conveyor belt assembly 74 or any other suitable device, mechanism, assembly, or combination thereof adapted to convey an amount of aggregate material. Preferred aggregate material conveyor belt assembly 74 also comprises aggregate material belt scale 76 which is adapted to weigh the amount of aggregate material on the conveyor belt assembly. It is contemplated within the scope of the invention, however, that the aggregate material source may determine the amount of aggregate material provided to the asphalt mix by any suitable means such as weight, volume, and the like. Preferred control system 10 also comprises aggregate material screens 78 which are adapted to screen the amount of aggregate material before it is mixed with the other components of the asphalt mix. While FIG. 1 illustrates the preferred configuration and arrangement of the aggregate material source, it is contemplated within the scope of the invention that the aggregate material source may be of any suitable configuration and arrangement.

Still referring to FIG. 1, preferred control system 10 further includes aggregate material sensor 80 which is adapted to determine an amount of aggregate material moisture contained in the amount of aggregate material. Preferred aggregate material sensor 80 may be any sensor adapted to determine the amount of aggregate material moisture contained in the amount of aggregate material such as an infrared sensor, a microwave sensor, a radioactive material based sensor, and the like. While FIG. 1 illustrates the preferred configuration and arrangement of the aggregate material sensor, it is contemplated within the scope of the invention that the aggregate material sensor may be of any suitable configuration and arrangement. It is also contemplated within the scope of the invention that more than one aggregate material sensor may be provided.

Still referring to FIG. 1, preferred control system 10 still further includes a recycled asphalt shingles source which is adapted to provide an amount of recycled asphalt shingles to the asphalt mix. The preferred recycled asphalt shingles source comprises a container such as RAS bin 90. Preferred RAS bin 90 is adapted to receive, hold, and discharge an amount of recycled asphalt shingles. Preferably, the amount of recycled asphalt shingles is conveyed from the recycled asphalt shingles source by conveyor belt assembly 26 or any other suitable device, mechanism, assembly, or combination thereof adapted to convey an amount of recycled asphalt shingles. Preferred conveyor belt assembly 26 also comprises belt scale 28 which is adapted to weigh the amount of recycled asphalt shingles on the conveyor belt assembly. It is contemplated within the scope of the invention, however, that the recycled asphalt shingles source may determine the amount of recycled asphalt shingles provided to the asphalt mix by any suitable means such as weight, volume, and the like. While FIG. 1 illustrates a belt scale that also weighs recycled asphalt pavement provided by the recycled asphalt pavement source, it is contemplated within the scope of the invention that there may be separate devices, mechanisms, assemblies, or combinations thereof adapted to determine the amounts of recycled asphalt shingles and the amounts of recycled asphalt pavement.

Still referring to FIG. 1, preferred control system 10 also comprises RAS screens 30 which are adapted to screen the amount of recycled asphalt shingles before it is mixed with the other components of the asphalt mix. While FIG. 1 illustrates RAS screens that also screen recycled asphalt pavement provided by the recycled asphalt pavement source, it is contemplated within the scope of the invention that there may be separate devices, mechanisms, assemblies, or combinations thereof adapted to screen the recycled asphalt shingles and the recycled asphalt pavement. Further, while FIG. 1 illustrates the preferred configuration and arrangement of the recycled asphalt shingles source, it is contemplated within the scope of the invention that the recycled asphalt shingles source may be of any suitable configuration and arrangement. It is also contemplated within the scope of the invention that the preferred control system may not include a recycled asphalt pavement source.

Still referring to FIG. 1, preferred control system 10 also comprises recycled asphalt shingles moisture sensor 40 which is adapted to determine an amount of RAS moisture contained in the amount of recycled asphalt shingles. Preferred recycled asphalt shingles sensor 40 may be any suitable type of sensor adapted to determine the amount of RAS moisture contained in the amount of recycled asphalt shingles such as an infrared sensor, a microwave sensor, a radioactive material based sensor, and the like. While FIG. 1 illustrates a recycled asphalt shingles sensor that also determines the amount of RAP moisture in an amount of recycled asphalt pavement provided by the recycled asphalt pavement source, it is contemplated within the scope of the invention that there may be separate devices, mechanisms, assemblies, or combinations thereof adapted to determine the amounts of moisture in recycled asphalt shingles and the amounts of moisture in recycled asphalt pavement. It is also contemplated within the scope of the invention that preferred control system 10 comprises asphalt content sensor 100 which is adapted to determine the amount of liquid asphalt cement contained in an amount of recycled asphalt pavement and/or an amount of recycled asphalt shingles. It is further contemplated within the scope of the invention that preferred control system 10 may comprise separate sensors for determining the amount of liquid asphalt cement contained in an amount of recycled asphalt pavement and the amount of liquid asphalt cement contained in an amount of recycled asphalt shingles. While FIG. 1 illustrates the preferred configuration and arrangement of the recycled asphalt shingles sensor, it is contemplated within the scope of the invention that the recycled asphalt shingles sensor may be of any suitable configuration and arrangement. It is also contemplated within the scope of the invention that more than one recycled asphalt shingles sensor may be provided. It is also contemplated within the scope of the invention that the preferred control system may not include a recycled asphalt pavement sensor.

Still referring to FIG. 1, preferred control system 10 further comprises water source 110 which is adapted to provide an amount of water to the asphalt mix. Preferred water source 110 comprises a container such as water tanks 112. Preferred water tanks 112 are adapted to receive, hold, and discharge an amount of water. Preferably, the amount of water is conveyed from water source 110 by a conduit, pipe, tube, or any other suitable device, mechanism, assembly, or combination thereof adapted to convey an amount of water. In the preferred embodiments, water source 110 is adapted to provide an amount of water to the amount of liquid asphalt cement as a percentage of the amount of liquid asphalt cement, but it is contemplated within the scope of the invention that the amount of water provided by the water source may be provided to any component of the asphalt mix in any suitable amount. Preferred water source 110 comprises means for determining a temperature of the amount of water provided by the water source to the asphalt mix. Preferred means for determining a temperature of the amount of water provided by the water source to the asphalt mix comprises a thermometer 114 disposed on water source 110, but it is contemplated within the scope of the invention that the means for determining a temperature of the amount of water provided by the water source to the asphalt mix may be any suitable device, mechanism, assembly, or combination thereof and may be disposed in any suitable location. While FIG. 1 illustrates the preferred configuration and arrangement of the water source, it is contemplated within the scope of the invention that the water source may be of any suitable configuration and arrangement. It is also contemplated within the scope of the invention that the preferred control system may not include a water source.

Still referring to FIG. 1, preferred control system 10 still further comprises water meter 120 which is adapted to determine the amount of water provided by water source 110 to the asphalt mix. Preferred water meter 120 is adapted to determine the mass flow rate of the amount of water provided by water source 110. It is contemplated within the scope of the invention, however, that the water meter may determine the amount of water provided by the water source by any suitable means such as weight, volume, and the like. It is also contemplated within the scope of the invention that more than one water meter may be provided. It is also contemplated within the scope of the invention that the preferred control system may not include a water meter.

Still referring to FIG. 1, preferred control system 10 still further comprises burner assembly 130 which is adapted to heat and dry the components of the asphalt mix and has a variable firing rate. More particularly, preferred burner assembly 130 comprises a means for measuring and adjusting the flow rate of fuel to the burner assembly such as fuel metering valve 132. It is contemplated within the scope of the invention that preferred burner assembly also comprises a means for adjusting the flow rate of combustion air to the burner assembly such as combustion air metering valve 134. Preferred control system 10 is adapted to control the flow rate of fuel to burner assembly 130 based on data relating to operating conditions from a plurality of sources in an asphalt plant which is collected substantially continuously and substantially in real time. Based on the operating conditions data collected substantially continuously and substantially in real time, preferred control system 10 calculates the required heat input from burner assembly 130, calculates the required fuel flow rate, and adjusts the means for adjusting the flow rate of fuel to the burner assembly in order to convey the required fuel flow rate. Similarly, preferred control system 10 is adapted to control the flow rate of combustion air to burner assembly 130 based on data relating to operating conditions from a plurality of sources in an asphalt plant which is collected substantially continuously and substantially in real time. Based on the operating conditions data collected substantially continuously and substantially in real time, preferred control system 10 calculates the required heat input from burner assembly 130, calculates the required combustion air flow rate, and adjusts the means for adjusting the flow rate of combustion air to the burner assembly in order to convey the required combustion air flow rate. Preferred burner assembly 130 is disposed adjacent to dryer 136 at burner end 138 of the dryer. Preferably, aggregate material enters aggregate end 140 of the dryer which is opposite burner end 138. Preferred dryer 136 comprises an inner drum. While FIG. 1 illustrates the preferred burner assembly and dryer, it is contemplated within the scope of the invention that that the control system comprises any suitable burner assembly and dryer.

Still referring to FIG. 1, preferred control system 10 also includes means for determining an exhaust gas temperature which is adapted to determine the exhaust gas temperature in baghouse 141. Preferably, the exhaust gas temperature in baghouse 141 is used as an input in the mass, heat, and moisture balance calculations performed by control system 10. It is contemplated within the scope of the invention that the exhaust gas temperature in the baghouse may be controlled directly through a heat source such as a heater or indirectly through increasing or decreasing the humidity level in the baghouse. It is also contemplated within the scope of the invention that a predetermined target baghouse temperature may be used as an input in the mass, heat, and moisture balance calculations performed by control system 10. Preferred means for determining an exhaust gas temperature is thermometer 142 disposed in the baghouse, however, it is contemplated within the scope of the invention that the means for determining an exhaust gas temperature may be any suitable device, mechanism, assembly, or combination thereof adapted to determine the temperature of exhaust gas and may be disposed in any suitable location. It is also contemplated within the scope of the invention that the preferred control system may not include a means for determining an exhaust gas temperature.

Still referring to FIG. 1, preferred control system 10 further includes means for determining a baghouse humidity which is adapted to determine the humidity level in baghouse 141. Preferred means for determining a baghouse humidity is humidity sensor 150 disposed in baghouse 141, however, it is contemplated within the scope of the invention that the means for determining a baghouse humidity level may be any suitable device, mechanism, assembly, or combination thereof adapted to determine the humidity level in the baghouse and may be disposed in any suitable location. It is also contemplated within the scope of the invention that the preferred control system may not include a means for determining a baghouse humidity level.

Still referring to FIG. 1, preferred control system 10 still further includes means for determining a final asphalt mix temperature which is adapted to determine the final temperature of the asphalt mix. Preferred means for determining a final asphalt mix temperature is thermometer 160 disposed adjacent to burner assembly 130, however, it is contemplated within the scope of the invention that the means for determining the final temperature of the asphalt mix may be any suitable device, mechanism, assembly, or combination thereof adapted to determine the final temperature of the asphalt mix and may be disposed in any suitable location. It is also contemplated within the scope of the invention that the preferred control system may not include a means for determining a final asphalt mix temperature.

Still referring to FIG. 1, preferred control system 10 also comprises controller 170 such as a microprocessor or some other programmable logic controller. Preferred controller is adapted to communicate with recycled the asphalt pavement source, recycled asphalt pavement sensor 40, liquid asphalt cement source 50, liquid asphalt cement meter 60, aggregate material source 70, aggregate material sensor 80, the recycled asphalt shingles source, recycled asphalt shingles sensor 100, water source 110, water meter 120, burner assembly 130, the means for determining an exhaust gas temperature, the means for determining a baghouse humidity, and the means for determining a final asphalt mix temperature. More particularly, preferred controller 170 collects data from the recycled asphalt pavement source, recycled asphalt pavement sensor 40, liquid asphalt cement source 50, liquid asphalt cement meter 60, aggregate material source 70, aggregate material sensor 80, the recycled asphalt shingles source, recycled asphalt shingles sensor 100, water source 110, water meter 120, burner assembly 130, the means for determining an exhaust gas temperature, the means for determining a baghouse humidity, and the means for determining a final asphalt mix temperature substantially continuously and substantially in real time. Preferably, the data that the controller collects substantially continuously and substantially in real time from the different sources in an asphalt plant relates to the operating conditions of the different sources.

Further, based on the data collected from the different sources in an asphalt plant, preferred controller 170 calculates an optimal firing rate for burner assembly 130 substantially continuously and substantially in real time. Preferred controller 170 continuously runs heat, mass, and moisture balance calculations to determine the required heat input in real time and adjusts the flow rate of fuel and/or combustion air to burner assembly 130 to provide the required heat input to the asphalt mix. Preferably, a predetermined target asphalt mix temperature is used by controller 170 as a reference and means of making a biasing correction for any error in the heat, mass, and moisture balance. In addition to the predetermined target asphalt mix temperature, preferred controller 170 uses the actual and predetermined target baghouse temperatures and the calculations based on the data collected from the different sources in an asphalt plant to automatically determine the necessary rate of fuel and/or combustion air flow to burner assembly 130 and automatically control the variable firing rate of burner assembly 130 substantially continuously and substantially in real time. Preferably, the variable firing rate of burner assembly 130 is substantially equal to the optimal firing rate calculated by controller 170, and the final fuel and/or combustion air flow rate adjustment is made based at least in part on the final asphalt mix temperature after the process has reached a fairly stable condition following a start-up or a significant change to operating conditions.

Still referring to FIG. 1, it is contemplated within the scope of the invention that additional components may be added to the asphalt mix such as lime from lime source 180 and mineral fillers from mineral fillers source 190. Preferred control system 10 may further comprise temperature sensors to measure the temperatures of such additional components. Preferred control system 10 may still further comprise flow rate meters, scales, or any other suitable device, mechanism, assembly, or combination thereof to measure the amounts of such additional components. The exemplary asphalt plant also comprises silos 200, power center 210, and final mix conveyor 220.

The preferred embodiments of the invention further comprise a method for controlling the temperature of an asphalt mix. The preferred method comprises providing a control system for controlling the temperature of the asphalt mix. The preferred control system comprises a recycled asphalt pavement source that is adapted to provide an amount of recycled asphalt pavement to the asphalt mix, a recycled asphalt pavement sensor that is adapted to determine an amount of RAP moisture contained in the amount of recycled asphalt pavement, a liquid asphalt cement source that is adapted to provide an amount of liquid asphalt cement to the asphalt mix, and a liquid asphalt cement meter that is adapted to determine the amount of liquid asphalt cement provided by the liquid asphalt cement source to the asphalt mix. The preferred control system also comprises a burner assembly having a variable firing rate, a dryer that disposed adjacent the burner assembly, and a controller that is adapted to communicate with the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, and the burner assembly. In the preferred embodiments of the control system, the controller automatically controls the variable firing rate of the burner assembly. The preferred method also comprises automatically controlling the variable firing rate of the burner assembly.

In other preferred embodiments of the method for controlling the temperature of an asphalt mix, the control system further comprises an aggregate material source that is adapted to provide an amount of aggregate material to the asphalt mix, an aggregate material sensor that is adapted to determine an amount of aggregate material moisture contained in the amount of aggregate material, a recycled asphalt shingles source that is adapted to provide an amount of recycled asphalt shingles to the asphalt mix, a recycled asphalt shingles sensor that is adapted to determine an amount of RAS moisture contained in the amount of recycled asphalt shingles, a water source that is adapted to provide an amount of water to the asphalt mix, a water meter that is adapted to determine the amount of water provided by the water source to the asphalt mix, a means for determining a temperature of the amount of liquid asphalt cement, a means for determining a temperature of the amount of water provided by the water source to the asphalt mix, a means for determining an exhaust gas temperature, a means for determining a baghouse humidity, and a means for determining a final asphalt mix temperature. In other preferred embodiments of the method for controlling the temperature of an asphalt mix, the method also comprises the controller communicating with the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, the aggregate material source, the aggregate material sensor, the recycled asphalt shingles source, the recycled asphalt shingles sensor, the water source, the water meter, the burner assembly, the means for determining a temperature of the amount of liquid asphalt cement, the means for determining an exhaust gas temperature, the means for determining a baghouse humidity, and the means for determining a final asphalt mix temperature.

More particularly, in the preferred methods for controlling the temperature of an asphalt mix, the method comprises the controller collecting data from the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, the aggregate material source, the aggregate material sensor, the recycled asphalt shingles source, the recycled asphalt shingles sensor, the water source, the water meter, the burner assembly, the means for determining a temperature of the amount of liquid asphalt cement, the means for determining an exhaust gas temperature, the means for determining a baghouse humidity, and the means for determining a final asphalt mix temperature substantially continuously and substantially in real time. Preferably, the data that the controller collects substantially continuously and substantially in real time from the different sources in an asphalt plant relates to the operating conditions of the different sources. Also in the preferred embodiments of the method for controlling the temperature of an asphalt mix, the method comprises the controller calculating an optimal firing rate for the burner assembly substantially continuously and substantially in real time based on the data collected from the different sources in an asphalt plant. In addition, in the preferred embodiments of the method for controlling the temperature of an asphalt mix, the method comprises the controller automatically controlling the variable firing rate of the burner assembly substantially continuously and substantially in real time using the calculations based on the data collected from the different sources in an asphalt plant. In the preferred methods for controlling the temperature of an asphalt mix, the variable firing rate of the burner assembly is substantially equal to the optimal firing rate calculated by the controller.

In operation, several advantages of the preferred embodiments of the apparatus and method for a control system for controlling the temperature of an asphalt mix are achieved. For example, the preferred embodiments of the invention claimed herein provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that is substantially completely automated. The preferred embodiments of the invention claimed herein also provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that collects data relating to operating conditions from multiple sources in an asphalt plant substantially continuously and substantially in real time. The preferred embodiments of the invention claimed herein further provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that analyzes operating conditions data from multiple sources in an asphalt plant and calculates an optimal firing rate for a burner assembly based upon the operating conditions data substantially continuously and substantially in real time. The preferred embodiments of the invention claimed herein still further provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that precisely and automatically controls the firing rate of a burner assembly substantially continuously and substantially in real time.

In addition, the preferred embodiments of the invention claimed herein provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that includes a burner assembly that fires at an optimal firing rate substantially continuously. Further, the preferred embodiments of the invention claimed herein provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that produces an asphalt mix that is neither over-heated nor under-heated. Still further, the preferred embodiments of the invention claimed herein provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that maximizes burner assembly and material efficiency and minimizes costly fuel consumption and material waste, particularly at start-up and shut-down. The preferred embodiments of the invention claimed herein also provide an apparatus and method for a control system for controlling the temperature of an asphalt mix that minimizes or eliminates human labor for monitoring and adjustments.

Although this description contains many specifics, these should not be construed as limiting the scope of the invention but as merely providing illustrations of some of the presently preferred embodiments thereof, as well as the best mode contemplated by the inventors of carrying out the invention. The invention, as described herein, is susceptible to various modifications and adaptations, and the same are intended to be comprehended within the meaning and range of equivalents of the appended claims. 

What is claimed is:
 1. A control system for controlling the temperature of an asphalt mix, said control system comprising: (a) a recycled asphalt pavement source, said recycled asphalt pavement source being adapted to provide an amount of recycled asphalt pavement to the asphalt mix; (b) a recycled asphalt pavement sensor, said recycled asphalt pavement sensor being adapted to determine an amount of RAP moisture contained in the amount of recycled asphalt pavement; (c) a liquid asphalt cement source, said liquid asphalt cement source being adapted to provide an amount of liquid asphalt cement to the asphalt mix; (d) a liquid asphalt cement meter, said liquid asphalt cement meter being adapted to determine the amount of liquid asphalt cement provided by the liquid asphalt cement source to the asphalt mix; (e) a burner assembly, said burner assembly having a variable firing rate; (f) a dryer, said dryer being disposed adjacent the burner assembly; (g) a controller, said controller being adapted to communicate with the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, and the burner assembly; wherein the controller automatically controls the variable firing rate of the burner assembly.
 2. The control system of claim 1 wherein the controller also collects data from the recycled asphalt pavement source, the recycled asphalt pavement sensor, and the liquid asphalt cement meter substantially continuously and substantially in real time.
 3. The control system of claim 1 wherein the controller also calculates an optimal firing rate for the burner assembly substantially continuously and substantially in real time.
 4. The control system of claim 3 wherein the variable firing rate of the burner assembly is substantially equal to the optimal firing rate.
 5. The control system of claim 1 wherein the controller also controls the variable firing rate of the burner assembly substantially continuously and substantially in real time.
 6. The control system of claim 1 further comprising: (h) an aggregate material source, said aggregate material source being adapted to provide an amount of aggregate material to the asphalt mix; (i) an aggregate material sensor, said aggregate material sensor being adapted to determine an amount of aggregate material moisture contained in the amount of aggregate material; wherein the controller is also adapted to communicate with the aggregate material source and the aggregate material sensor.
 7. The control system of claim 6 wherein the controller also collects data from the aggregate material source and the aggregate material sensor substantially continuously and substantially in real time.
 8. The control system of claim 6 wherein the controller also calculates an optimal firing rate for the burner assembly substantially continuously and substantially in real time.
 9. The control system of claim 8 wherein the variable firing rate of the burner assembly is substantially equal to the optimal firing rate.
 10. The control system of claim 6 wherein the controller also controls the variable firing rate of the burner assembly substantially continuously and substantially in real time.
 11. The control system of claim 1 further comprising: (h) a recycled asphalt shingles source, said recycled asphalt shingles source being adapted to provide an amount of recycled asphalt shingles to the asphalt mix; (i) a recycled asphalt shingles sensor, said recycled asphalt shingles sensor being adapted to determine an amount of RAS moisture contained in the amount of recycled asphalt shingles; wherein the controller is also adapted to communicate with the recycled asphalt shingles source and the recycled asphalt shingles sensor.
 12. The control system of claim 11 wherein the controller also collects data from the recycled asphalt shingles source and the recycled asphalt shingles sensor substantially continuously and substantially in real time.
 13. The control system of claim 11 wherein the controller also calculates an optimal firing rate for the burner assembly substantially continuously and substantially in real time.
 14. The control system of claim 13 wherein the variable firing rate of the burner assembly is substantially equal to the optimal firing rate.
 15. The control system of claim 11 wherein the controller also controls the variable firing rate of the burner assembly substantially continuously and substantially in real time.
 16. The control system of claim 1 further comprising: (h) a water source, said water source being adapted to provide an amount of water to the asphalt mix; (i) a water meter, said water meter being adapted to determine the amount of water provided by the water source to the asphalt mix; wherein the controller is also adapted to communicate with the water source and the water meter.
 17. The control system of claim 16 wherein the water source comprises a means for determining a temperature of the amount of water provided by the water source to the asphalt mix.
 18. The control system of claim 16 wherein the controller also collects data from the water source and the water meter substantially continuously and substantially in real time.
 19. The control system of claim 16 wherein the controller also calculates an optimal firing rate for the burner assembly substantially continuously and substantially in real time.
 20. The control system of claim 19 wherein the variable firing rate of the burner assembly is substantially equal to the optimal firing rate.
 21. The control system of claim 16 wherein the controller also controls the variable firing rate of the burner assembly substantially continuously and substantially in real time.
 22. The control system of claim 1 further comprising: (h) a means for determining an exhaust gas temperature; wherein the controller is also adapted to communicate with the means for determining an exhaust gas temperature.
 23. The control system of claim 22 wherein the controller also collects data from the means for determining an exhaust gas temperature substantially continuously and substantially in real time.
 24. The control system of claim 22 wherein the controller also calculates an optimal firing rate for the burner assembly substantially continuously and substantially in real time.
 25. The control system of claim 24 wherein the variable firing rate of the burner assembly is substantially equal to the optimal firing rate.
 26. The control system of claim 22 wherein the controller also controls the variable firing rate of the burner assembly substantially continuously and substantially in real time.
 27. The control system of claim 1 further comprising: (h) a means for determining a baghouse humidity; wherein the controller is also adapted to communicate with the means for determining a baghouse humidity.
 28. The control system of claim 27 wherein the controller also collects data from the means for determining a baghouse humidity substantially continuously and substantially in real time.
 29. The control system of claim 27 wherein the controller also calculates an optimal firing rate for the burner assembly substantially continuously and substantially in real time.
 30. The control system of claim 29 wherein the variable firing rate of the burner assembly is substantially equal to the optimal firing rate.
 31. The control system of claim 27 wherein the controller also controls the variable firing rate of the burner assembly substantially continuously and substantially in real time.
 32. The control system of claim 1 further comprising: (h) a means for determining a final asphalt mix temperature; wherein the controller is also adapted to communicate with the means for determining a final asphalt mix temperature.
 33. The control system of claim 32 wherein the controller also collects data from the means for determining a final asphalt mix temperature substantially continuously and substantially in real time.
 34. The control system of claim 32 wherein the controller also calculates an optimal firing rate for the burner assembly substantially continuously and substantially in real time.
 35. The control system of claim 34 wherein the variable firing rate of the burner assembly is substantially equal to the optimal firing rate.
 36. The control system of claim 32 wherein the controller also controls the variable firing rate of the burner assembly substantially continuously and substantially in real time.
 37. A method for controlling the temperature of an asphalt mix, said method comprising: (a) providing a control system for controlling the temperature of the asphalt mix, said control system comprising: (i) a recycled asphalt pavement source, said recycled asphalt pavement source being adapted to provide an amount of recycled asphalt pavement to the asphalt mix; (ii) a recycled asphalt pavement sensor, said recycled asphalt pavement sensor being adapted to determine an amount of RAP moisture contained in the amount of recycled asphalt pavement; (iii) a liquid asphalt cement source, said liquid asphalt cement source being adapted to provide an amount of liquid asphalt cement to the asphalt mix; (iv) a liquid asphalt cement meter, said liquid asphalt cement meter being adapted to determine the amount of liquid asphalt cement provided by the liquid asphalt cement source to the asphalt mix; (v) a burner assembly, said burner assembly having a variable firing rate; (vi) a dryer, said dryer being disposed adjacent the burner assembly; (vii) a controller, said controller being adapted to communicate with the recycled asphalt pavement source, the recycled asphalt pavement sensor, the liquid asphalt cement source, the liquid asphalt cement meter, and the burner assembly; wherein the controller automatically controls the variable firing rate of the burner assembly; and (b) automatically controlling the variable firing rate of the burner assembly. 